Apparatus and method for manufacturing crash pad

ABSTRACT

An apparatus and method for manufacturing a crash pad with a foaming layer formed by injecting a foaming solution between a core and a skin are disclosed. The apparatus includes a first mold and a second mold used to form the skin by injecting molten resin of a skin material into a skin forming cavity when the first and second molds are combined. In addition, a third mold and the fourth mold form the core by injecting molten resin of a core material into a core forming cavity when the third and fourth molds are combined. The first mold has a vacuum aperture in an inner surface of the first mold to adsorb and fix a thread to implement a stitch before the forming of the skin, and the vacuum aperture exerts a vacuum suctioning force to absorb and fix via a vacuum pressure applied from a vacuum pressure providing unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 13/966,783 filed Aug. 14, 2013 now issued U.S. Pat. No. 9,346,199which claims under 35 U.S.C. §119(a) the benefit of Korean PatentApplication No. 10-2012-0144400 filed Dec. 12, 2012, the entire contentsof which are incorporated herein by reference.

BACKGROUND

(a) Technical Field

The present invention relates to an apparatus and method formanufacturing a crash pad. More particularly, the present inventionrelates to an apparatus and method for manufacturing a crash pad, whichcan improve the productivity and decrease the costs for equipment andmanufacturing by reducing the number of molds, the number ofinstallation components and the number of processes and omitting thehandwork, and can increase the degree of freedom of embossment design onthe surface of a skin while overcoming an excessive loss due to aleakage of foaming liquid.

(b) Background Art

In general, crash pads are used as an interior material installed atfront of driver and passenger seats to protect passengers at the time ofcollision between the passengers and the crash pad due to a vehicleaccident. These crush pads are formed of foaming materials to achieveelastic cushion performance and impact absorbing characteristics to acertain degree while providing an aesthetically enhanced surfacecondition.

Crash pads for a vehicle usually include a skin which is a surfacematerial that provides an enhanced aesthetic surface condition and acore that serves as a framework of the crash pad inside the skin. Afoaming layer such as polypropylene (PP) foam and/or polyurethane (PU)foam is interposed between the skin and the core to provide cushioningperformance and impact absorbing performance.

FIG. 1 is an exemplary view illustrating a process of manufacturing atypical crash pad. A core 1, a skin 2, and a foaming layer 3 are formedby a polymer injection molding method, a vacuum adsorption moldingmethod and a foaming molding method, respectively, all processes ofwhich will be described in detail with reference to FIG. 1 as follows.

First, a polymer resin material 1 a is injected at a lower pressure intoan injection mold including upper and lower molds 4 and 5 to form a core1, and separately, the skin 2 that is preheated in a male type of vacuumforming mold 6 is inserted and molded by the vacuum adsorption method.

In particular, although not shown in the drawing, fine vacuum aperturesfor vacuum adsorbing the skin 2 in the vacuum forming mold 6 are formedin the vacuum forming mold 6, and the vacuum apertures are connected toone passageway in the mold and then connected to a large capacity of anexternal vacuum pump. Additionally, foaming liquid 3 a is injected intothe core 1 of lower mold 5, and then a forming upper mold 7 attached tothe skin 2 is closed, compressing and joining the skin 2 attached to theupper mold 7 onto foaming liquid 3 a of the lower mold 5.

Thereafter, an unnecessary edge portion (e.g., leakage portion offoaming liquid) of the skin 2 and the foaming layer 3 that are formed iscut and removed (e g, trimming), or the edge portion of the skin 2 isadhered and fixed to the core 1 by an adhesive such that the foaminglayer 3 is covered.

However, this typical manufacturing method has limitations as follows.

First, since the core 1, the skin 2 and the foaming layer 3 need to bemolded at separate molds, respectively, a total of three molds (e.g.,core injection upper and lower mold, vacuum forming mold, and foamingupper mold) are required to manufacture the crash pad. Thus, there is alimitation in that the investment and manufacturing cost such as moldingcost increase.

Furthermore, since the lower mold 5 and the foaming upper molding 7 isopened at the edge portion of a cavity even when in closed state, aleakage of foaming liquid may occur at the opened edge portion thus,causing an excessive loss of foaming liquid and an increase of themanufacturing cost.

As described in FIG. 1D, after the manufacturing, a separate process inwhich the edge portion of the skin 2 and the edge portion solidified dueto the leakage of foaming liquid are separately cut or only a leakageportion is cut and then the edge portion of the skin 2 is covered andadhered by an adhesive is required to manufacture the crash pad.Additionally, since foaming liquid needs to be injected into the openedcavity (e.g., foaming cavity), there may be difficulty in accuratelymaintaining and controlling the injection temperature of foaming liquidwithin a regulated temperature range.

In addition, in a structure in which the foaming cavity is opened orfoaming liquid is capable of leaking, the foaming layer 3 needs to bedesigned to have a substantially uniform thickness of about 5 mm or moredue to early solidification of foaming liquid. This may be a cause ofreducing the design degree of freedom of the crash pad (e g, limitationof open foaming).

In order to solve these limitations, a molding apparatus has beenproposed that seals the foaming cavity by adhering the edge portion ofthe skin closely to the core using a slide mold while integrating thevacuum foaming mold and the foaming upper mold into one common mold.This provides a benefit of solving a limitation of an excessive loss offoaming liquid, and enables the improvement of the design degree offreedom of the crash pad.

FIG. 2 is an exemplary view illustrating a typical foaming integratedinjection molding apparatus including a slide mold that prevents aleakage of foaming liquid. In an apparatus for manufacturing a crashpad, the crash pad may be manufactured by an In-Mold Grain (IMG) foamingintegrated injection molding method. Specifically, the IMG foamingprocess refers to a method in which a skin is molded through skinheating and vacuum suctioning in a mold and simultaneously an embossmentis formed on the surface of the skin by forming the embossment on theinner surface of the mold (e.g., vacuum forming mold) to form a skin(e.g., thermoplastic olefin (TOP) material).

As shown in the drawing, when the core injection molds 10 and 11 arecombined, resin may be injected into the mold to form a core 1, andsimultaneously, a skin 2 is formed by vacuum adsorption in a vacuumforming mold 12. Thereafter, the mold is rotated and transferred by anupper rotating unit to allow the vacuum forming mold 12 with the skin 2to combine with the lower mold 11 with the core 1, and then foamingliquid is injected and foamed between the core 1 and the skin 2 to forma foaming layer 3.

When foaming liquid is injected, the slide mold 12 a allows the edgeportion of the skin 2 to adhere closely to the core 1 to seal a foamingcavity. In particular, the slide mold 12 a moves forward by apredetermined distance for the sealing during the foaming, and thenfixed to maintain the sealing. After the foaming, the slide mold 12 amoves backward to eject a product.

As shown in FIG. 3, the sealing is performed while a sealing protrusionpart 1 c formed on core 1 is overlapped with the skin 2. Thus,preventing the foaming liquid from leaking by the sealing protrusionpart 1 c.

This molding apparatus may substantially prevent a leakage of foamingliquid, and a part of molds are used in common, thereby reducing thenumber of molds, the mold cost, and the investment and manufacturingcost.

However, since an edge portion of the skin 2 is located under the slidemold 12 a, the edge portion of the skin 2 needs to be cut separately, oran end finishing process (e.g., end wrapping process) of the skin 2needs to be performed.

In a conventional crash pad manufacturing apparatus of the prior art,when the slide mold moves forward, the edge portion of the skin attachedto a vacuum forming mold is bent toward the end of a core to allow theedge portion of the skin to adhere closely to the core. Thus, thefoaming cavity may be entirely sealed by the edge portion of the skinadhering closely to the end of the core during the foaming process.

When foaming liquid is injected into the sealed forming cavity, afoaming layer may be formed in the sealed foaming cavity without aleakage of foaming liquid. Additionally, the skin end finishing process(e.g., end wrapping process) may be automatically performed while theedge portion of the skin bent by the slide mold is joined and fixed tothe end portion of the foaming layer. Thus, a leakage of foaming liquidmay be solved, and the cutting process or the wrapping process that hasbeen manually performed may both be omitted. In addition, theproductivity may be improved.

Moreover, according to another conventional molding apparatus, as shownin FIG. 2, since the vacuum adsorption molding of the skin is performed,apparatuses for the vacuum adsorption molding, i.e., an expensive moldwith fine vacuum apertures, a vacuum pump for the material adsorption,and a heater for heating a material before the molding are required.

FIG. 4 is an exemplary view illustrating a heater and a vacuum pumptogether with a molding apparatus. As shown in FIG. 4, a vacuum pump 13that applies a vacuum pressure to a vacuum aperture of a vacuum formingmold 12 and a heater 14 that heats a skin material 2 a before the skinmaterial 2 a is adsorbed to the vacuum forming mold 12 are provided.

To manufacture a crash pad by an IMG foaming integrated injectionmolding method using the vacuum pump 13 and the heater 14, the vacuumforming mold 12 that forms a fine embossment on the skin material (e.g.,TPO sheet) 2 a without an embossment, particularly, an expensive nickelelectroforming mold with fine vacuum apertures (e.g., fine apertures of50 μm to 200 μm) formed throughout the inner surface of the mold toadsorb the skin material 2 a to the inner surface of the mold arerequired. The heater 14 is needed to heat the skin material 2 a beforethe mold adsorption, and a separate transfer device (not shown) thattransfers the heated skin material 2 a to the vacuum forming mold 12 arerequired.

In addition, the embossment may be formed on the surface of the skinonly when the entire skin material can be adsorbed and fixed to theinner surface of the mold by applying a vacuum pressure via the vacuumaperture of the mold 12 and the material is strongly adsorbed to allowthe surface portion of the skin material to be inserted into theembossment portion on the inner surface of the mold. Accordingly, avacuum pressure that forms a strong suctioning force is required, andthus, a large capacity of vacuum pump and tank are required.

Finally, there is a limitation in that the equipment cost increases dueto the installation of a nickel electroforming mold, a heater, atransfer device, and a large capacity of vacuum pump and tank.

Hereinafter, a limitation regarding the product quality will bedescribed with reference to FIGS. 5 and 4. FIG. 5 is an exemplarycross-sectional view illustrating a skin during the vacuum forming, andFIG. 4 is an exemplary view of a part ‘A’.

FIG. 5 illustrates: (a) the skin material 2 a heated by the heater andinserted into the mold 12; (b) molding performed while the skin material2 a is vacuum adsorbed to the inner surface of the mold by a vacuumsuctioning force through a fine vacuum aperture of the mold 12; and (c)a state after the molding, which shows a typical limitation.

When a vacuum suctioning force is applied during the molding (b), thesurface portion of the skin material 2 a is inserted into the concaveembossment on the inner surface of the mold, and then a convexembossment 2 b is formed on the finally formed skin 2 as shown in FIG.5. In particular, in the IMG embossment molding method using the vacuumadsorption, the quality deterioration may occur as shown in FIG. 5,which is caused by the shrinkage and rebounding of the embossment 2 b ofthe skin 2 when the vacuum is released after the molding.

Additionally, to form the embossment 2 b in the skin 2, the surfaceportion of the skin material 2 a must be inserted into the embossmentportion 12 b on the inner surface of the mold 12 by the vacuumsuctioning force. In this case, an excessive vacuum time is spent, andthus the productivity decreases.

Furthermore, in the vacuum adsorption method, it may be difficult toform a sharp portion and deal with an undercut portion. In addition,when trying to implement a stitch 2 c on the surface of the skin 2, thestitch 2 c is also formed by the embossment portion 12 b in the innersurface of the mold 12. In particular, the stitch 2 c is a portion ofthe skin surface that protrudes at a specific location, corresponding tothe shape of the stitch on the surface of the skin 2.

Accordingly, as shown in FIG. 6, there is a limitation in that only astitch having the same color as the skin 2 can be implemented and therealistic feeling of the stitch 2 c is deteriorated.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY

The present invention provides an apparatus and method for manufacturinga crash pad, which can improve the productivity and decrease the costsfor equipment and manufacturing by reducing the number of molds, thenumber of installation components and the number of processes andomitting the handwork, and may increase the degree of freedom ofembossment design on the surface of a skin while overcoming an excessiveloss due to a leakage of foaming liquid.

The present invention also provides an apparatus and method formanufacturing a crash pad, which may improve the realistic feeling of astitch formed on the surface of a skin.

In one aspect, the present invention provides an apparatus formanufacturing a crash pad with a foaming layer formed by injectingfoaming solution between a core and a skin, the apparatus including: afirst mold and a second mold that form the skin by injecting moltenresin of a skin material into a skin forming cavity when the first andsecond molds are combined; and a third mold and a fourth mold that formthe core by injecting molten resin of a core material into a coreforming cavity when the third and fourth molds are combined, wherein thefirst mold has a vacuum aperture in an inner surface of the first moldto adsorb and fix a thread that implements a stitch before the formingof the skin, and the vacuum aperture exerts a vacuum suctioning forcethat absorbs and fixes via a vacuum pressure applied from a vacuumpressure providing unit.

In another aspect, the present invention provides a method formanufacturing a crash pad with a foaming layer formed by injectingfoaming solution between a core and a skin, the apparatus including:adsorbing and fixing a thread to an internal surface of a first mold toblock a vacuum aperture when a vacuum pressure is applied to the vacuumaperture, the thread forming a stitch part on a surface of the skin;forming the skin by injecting molten resin of a skin material when thefirst mold and a second mold are combined; forming the core by injectingmolten resin of a core material when a third mold and a fourth mold arecombined; and forming a foaming layer by injecting foaming liquid into afoaming cavity between the core and the skin after the mold is openedand then the first mold fixed with the skin and the fourth mold attachedwith the core are combined.

In still another aspect, the present invention provides a crash padmanufactured by the above method, the crash pad including a stitch partcomprising: an exposure part having a thread exposed on a surface of askin; and a hidden part having the thread buried in the surface of theskin.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will now bedescribed in detail with reference to certain exemplary embodimentsthereof illustrated the accompanying drawings which are givenhereinbelow by way of illustration only, and thus are not limitative ofthe present invention, and wherein:

FIG. 1 is an exemplary view illustrating a process of manufacturing atypical crash pad according to the related art;

FIG. 2 is an exemplary view illustrating a typical foaming integratedinjection molding apparatus comprising a slide mold according to therelated art;

FIG. 3 is an exemplary cross-sectional view of a part ‘A’ of FIG. 2according to the related art;

FIG. 4 is an exemplary view illustrating a typical molding apparatus andauxiliary installations including a heat and a vacuum pump according tothe related art;

FIG. 5 is an exemplary cross-sectional view illustrating a skin during atypical vacuum adsorption forming according to the related art;

FIG. 6 is an exemplary view illustrating the surface of a skinmanufactured by a typical method according to the related art;

FIGS. 7A and 7B are exemplary cross-sectional views illustrating aconfiguration of a crash pad manufacturing apparatus according to anexemplary embodiment of the present invention;

FIG. 8 is an exemplary cross-sectional view illustrating a process offorming an exposure part and a hidden part of a stitch according to anexemplary embodiment of the present invention; and

FIG. 9 is an exemplary view illustrating the surface of a skinmanufactured according to an exemplary embodiment of the presentinvention.

Reference numerals set forth in the Drawings includes reference to thefollowing elements as further discussed below:

 1: skin  2: core  3: forming layer 110: first mold 111: slide mold 112:embossment 113: fixing groove 114: vacuum aperture 115: thread 115a:exposure part 115b: hidden part 120: second mold 121: slide mold 122:injection passage 130: third mold 140: fourth mold

It should be understood that the accompanying drawings are notnecessarily to scale, presenting a somewhat simplified representation ofvarious exemplary features illustrative of the basic principles of theinvention. The specific design features of the present invention asdisclosed herein, including, for example, specific dimensions,orientations, locations, and shapes will be determined in part by theparticular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

Unless specifically stated or obvious from context, as used herein, theterm “about” is understood as within a range of normal tolerance in theart, for example within 2 standard deviations of the mean. “About” canbe understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%,0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear fromthe context, all numerical values provided herein are modified by theterm “about.”

Hereinafter reference will now be made in detail to various exemplaryembodiments of the present invention, examples of which are illustratedin the accompanying drawings and described below. While the inventionwill be described in conjunction with exemplary embodiments, it will beunderstood that present description is not intended to limit theinvention to those exemplary embodiments. On the contrary, the inventionis intended to cover not only the exemplary embodiments, but alsovarious alternatives, modifications, equivalents and other embodiments,which may be included within the spirit and scope of the invention asdefined by the appended claims.

It is understood that the term “vehicle” or “vehicular” or other similarterm as used herein is inclusive of motor vehicles in general such aspassenger automobiles including sports utility vehicles (SUV), buses,trucks, various commercial vehicles, watercraft including a variety ofboats and ships, aircraft, and the like, and includes hybrid vehicles,electric vehicles, plug-in hybrid electric vehicles, hydrogen-poweredvehicles and other alternative fuel vehicles (e.g., fuels derived fromresources other than petroleum). As referred to herein, a hybrid vehicleis a vehicle that has two or more sources of power, for example bothgasoline-powered and electric-powered vehicles.

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings so thatthose skilled in the art can easily carry out the present invention.

In an exemplary embodiment of present invention a skin may bemanufactured using an injection molding method instead of a vacuumadsorption molding method and an actual thread may be fixed on thesurface of a skin to implement a stitch upon injection molding of theskin.

The present invention may be applied to the manufacture of a crash padusing an In-Mold Grain (IMG) foaming integrated injection method. Sincean injection molding method may be used to form a skin instead of atypical vacuum adsorption molding method, a steel injection mold (e.g.,formed of a steel alloy material) may be used instead of an expensivenickel electroforming mold. In particular, similarly to the nickelelectroforming mold (e.g., vacuum forming mold), an embossment pattern(e.g., concave embossment) may be formed in the inner surface of thesteel injection mold.

However, the steel injection mold may have less vacuum apertures toadsorb and fix a thread unlike the nickel electroforming mold in whichfine vacuum apertures are evenly formed throughout the inner surface ofthe mold. In other words, in a typical vacuum forming mold that forms askin, since the skin needs to be adsorbed and fixed to be transferred toa foaming process and the embossment part needs to be vacuum adsorbedusing a vacuum suctioning force applied through a vacuum aperture, anumber of vacuum apertures must be evenly provided throughout the skin.

However, in the present invention, since the embossment part of the skinmay be formed using the injection molding method, a vacuum apertureinside the fixing groove that fixes a thread as described later has onlyto be provided in the skin forming mold. Accordingly, less vacuumapertures are required.

For reference, a means that fixes the injection molded skin to the moldfor transfer to the foaming process may include the vacuum apertures(and the vacuum suctioning force) and a slide mold of a skin formingupper mold described later. In particular, the vacuum suctioning forcemay assist the fixing force using the slide mold. Additionally, in atypical vacuum adsorption forming method, a suctioning force strongerthan the suctioning force for fixing the skin to form embossment in thesurface of the skin needs to be applied. However, in the presentinvention, since a vacuum pressure needs only to be applied to allow thethread and the skin to be adsorbed and fixed to a less number of vacuumapertures, a relatively small capacity of vacuum pressure providingunit, i.e., a small capacity of vacuum pump or tank may be used. Inaddition, since an injection mold method is used to form the skin in themold, a transfer device and a heater needed for material heating (e.g.preheating) in the vacuum adsorption molding may be omitted.

FIGS. 7A and 7B are exemplary cross-sectional views illustrating aconfiguration of a crash pad manufacturing apparatus according to anexemplary embodiment of the present invention, which also show amanufacturing process by stages.

FIG. 7A illustrates a thread adsorbed and fixed to an upper mold and aninjection of a core and a skin. FIG. 7B illustrates a foaming and anejecting of a product. As shown in FIGS. 7A and 7B, a crash padmanufacturing apparatus according to an exemplary embodiment of thepresent invention may include an upper mold 110 and a lower mold 120that form a skin, and an upper mold 130 and a lower mold 140 that form acore.

Hereinafter, the upper mold 110 and the lower mold 120 that form theskin will be referred to as a first mold and a second mold, and theupper mold 130 and the lower mold 140 that form the core will bereferred to as a third mold and a fourth mold.

The first mold 110 may become a steel injection mold as described above.In particular, the second mold 120 may also become a steel injectionmold. The third mold 130 and the fourth mold that form the core may besimilar to a typical configuration for injecting a core 1, and may alsobecome a steel injection mold.

However, when the first mold 110 attached with a skin 2 that isinjection molded and the fourth mold 140 with the core 1 injectionmolded are combined, a foaming cavity that forms a foaming layer 3 maybe formed between the skin 2 and the core 1. The first mold 110 and thefourth mold 140 may also be used as a mold for foaming (see foaming ofFIG. 7B). In other words, when the first mold 110 and the fourth mold140 are combined, a cavity between the core 1 and the skin fixed to themold may be a foaming cavity (e.g., forming cavity for foaming layer) inwhich the foaming may be performed. Thus, a product (e.g., crash pad)with a stack structure of the skin 2, the foaming layer 3, and the core1 may be manufactured. Additionally, the foaming cavity may form a spacesealed by a slide mold 111 of the first mold 110. The slide mold 111 ofthe first mold 110 may adhere an edge portion of the skin 2 closely toan edge portion of the core 1 to seal the edge portion of the foamingcavity.

Since the fourth mold 140 may be used as a lower mold for foaming aswell as core forming, the fourth mold 140 may include an injectionpassageway 141 for injecting molten polymer resin of a core materialinto the core forming cavity and a foaming liquid injection passageway142 for injecting foaming liquid which is a material of the foaminglayer into the foaming cavity. In particular, the foaming upper mold,i.e., the upper mold during the foaming process may become the firstmold 110.

Additionally, foaming liquid may be injected from the lower side of thecore 1 that is first formed through the foaming liquid injectionpassageway 142 disposed within the fourth mold 140. In particular, sincethe foaming liquid must be injected into a cavity, i.e., foaming cavitywith the skin 2 thereover through the core 1, an aperture 1 b may beformed in the core 1 to upwardly pass the foaming liquid before thefoaming process.

Accordingly, to form the aperture 1 b in the core 1, a pin part 131 maydownwardly protrude from the inner surface of the third mold 130 by asubstantial core forming thickness at a location (corresponding to thefoaming liquid injection passageway in a closed state of mold)corresponding to the foaming liquid injection passageway 142 of thefourth mold 140. Thus, when the third mold 130 and the fourth mold 140are combined into a closed state (e.g., a combined state), the pin part131 of the third mold 130 may be located at the foaming liquid injectionpassageway 142 of the fourth mold 140 within the core forming cavity(e.g., cavity of mold) between both molds. In particular, when moltenresin (e.g., injection liquid) that is a core material may be injectedthrough the injection passageway 141, the core 1 with the aperture 1 bformed by the pin part 131 may be formed.

In each mold described above, the first mold 110 and the third mold 130that are the upper molds may be a female type of mold, and the secondmold 120 and the fourth mold 140 that are the lower molds may be a maletype of mold.

On the other hand, when the first mold 110 and the second mold 120 thatform the skin may form a skin forming cavity (e.g., cavity of mold) whencombined, and as shown in FIG. 7b , molten resin (e.g., injectionliquid) that is a skin material may be injected into the skin formingcavity defined by the two molds to form the skin 2. Thus, an injectionpassageway 122 may be disposed in the second mold 120 to inject moltenresin into the skin forming cavity.

In this embodiment, a material having a low viscosity at a molten state,e.g., PP/SEBS-based TPO that is a mixed resin of polypropylene (PP) andstyrene-ethylene-butadiene-styrene (SEBS) may be used as a material formanufacturing the skin. Additionally, an embossment 112 may be formed inthe inner surface of the first mold 110. The embossment 112 may be aconcave embossment similar to the nickel electroforming mold used in atypical vacuum adsorption forming method.

However, in the first mold 110 according to this embodiment, theembossment 112 that forms a typical stitch part may be omitted. Instead,an actual thread may be used to form a stitch on the skin surface, andthe thread may be fixed on the inner surface of the first mold 110 priorto the skin injection.

In an exemplary embodiment, a fixing groove 113 may be longitudinallyformed along a part where the thread 115 is adsorbed and fixed on theinner surface of the first mold 110, and the thread may be inserted intoand seated in the fixing groove 113. The fixing groove 113 may belongitudinally formed along substantially the entire part where thethread 115 is fixed on the inner surface of the first mold 110. Inparticular, the fixing groove 113 may be formed in such a depth or widththat only a sectional portion of the thread 115 may be inserted into thefixing groove 113. In other words, the fixing groove 113 may be formedin such a depth or width that only a sectional portion of the thread 115may be inserted and the other portion of the thread 115 may protrude tothe exterior (see FIG. 8).

Furthermore, vacuum apertures 114 may be disposed in the inner surfaceof the first mold 110 at a predetermined interval along the fixinggroove 113. The vacuum apertures 114 may adsorb and fix the thread 115on the inner surface of the mold (see FIG. 8). In this embodiment, theinlet of the vacuum aperture 114 disposed in the inner surface of thefixing groove 113 may have a circular shape or an oblong shape along thelongitudinal direction (e.g., longitudinal direction of the fixinggroove) of the thread 115.

The vacuum apertures 114 may extend from the inlet located on the innersurface (e.g., inner surface of the fixing groove) of the mold to theinside of the mold to join into one passageway 114, and then may beconnected to a vacuum pump (not shown) that is an external vacuumpressure providing unit via a hose or a tube. Thus, when a vacuumpressure is applied to the vacuum aperture 114 by the vacuum pump, thethread 115 may be adsorbed and fixed to the inner side of the fixinggroove 113 via a vacuum suctioning force applied through the vacuumaperture 114. In particular, the thread 115 may be adsorbed and fixed tofully block the inlet of the vacuum aperture 114 to prevent the moltenresin for the skin injection forming, i.e., injection liquid of the skinmaterial from penetrating into the vacuum aperture 114.

To prevent the penetration of the molten resin into the vacuum aperture,the inlet of the vacuum aperture 114 may be formed a size and shape thatfully blocks the inlet of the vacuum aperture 114 by the thread 115adsorbed and fixed to the fixing groove 113. For example, the inlet ofthe vacuum aperture 114 may have a diameter (e.g., when the inlet iscircular) or a width (e.g., when the inlet is oblong in one direction)smaller than the diameter of the thread 115 (see FIG. 8).

FIG. 8 illustrates: 1) the thread 115 adsorbed and fixed to the innerside of the fixing groove 113 by a suctioning force applied through thevacuum aperture 114 before the skin forming; 2) the injection molding ofthe skin performed by injecting injection liquid while the thread 115 isblocking the vacuum aperture 114; and 3) a product ejected by releasingvacuum when the foaming layer 3 is formed after the injection of thecore and the skin 2.

Thus, when the thread 115 may be adsorbed and fixed to the fixing groove113 of the first mold 110, and the skin is injection-molded, then astitch may be formed while the thread 115 is being attached to thesurface of the skin 2 that is molded, and thus the actual thread mayenable the stitch (115 a and 115 b of FIG. 9) on the skin surface. Inparticular, the vacuum pressure may maintain the blocking condition ofthe vacuum aperture 114 by the thread 115 while fixing the location ofthe thread 115 inserted into the fixing groove 113. In this condition,the vacuum pressure may operate as a fixing force that blocks the vacuumaperture 114 to prevent the injection liquid from penetrating into thevacuum aperture 114.

Additionally, the vacuum pressure may adsorb and fix the thread 115 intothe fixing groove 133 to prevent the entire thread from completelypenetrating into the injection liquid, and may assist the skin fixing byapplying a vacuum suction force to the skin 2 through the vacuumaperture 114 when the skin 2 that is injection molded is transferred tothe foaming process (e.g., the first mold is transferred to the fourthmold and then combined therewith; see FIGS. 7A and 7B). In this process,since only a smaller vacuum pressure that may adsorb only the thread 115and the skin 2 need be provided, a substantially small capacity ofvacuum pump and tank may be used compared to a related art (e.g., asubstantially large suctioning force required to form embossment in arelated art is not needed)

Additionally, since the skin 2 is injection molded, a heater needed forthe vacuum adsorption forming may be omitted. The freedom degree of theembossment shape may also be enhanced. Since the skin 2 may bemanufactured by the injection molding, a sharp shape or an undercutshape may be implemented along the embossment shape of the first mold110 to form the skin, and a deformation due to shrinkage or reboundingoccurring after molding by the vacuum adsorption method may beprevented.

On the other hand, a slide mold 111 may be disposed within the firstmold 110 to be movable forward and backward for the sealing of thefoaming cavity. The slide mold 111 may move forward under the control ofa controller (not shown) during the foaming process, supporting the skin2 transferred to the foaming process after the molding to fix the skin 2to the first mold 110 and sealing an edge portion of the foaming cavityby adhering and fixing an edge portion of the skin 2 closely to an edgeportion of the core 1 in the foaming process.

Since the slide mold 111 may adhere the skin 2 closely to the core 1 atthe edge portion of the foaming cavity, the slide mold 111 may bedisposed along the edge portion of the foaming cavity of the mold. Inparticular, since the slide mold 111 needs to move forward to seal theedge portion of the foaming cavity, the slide mold 111 may include aplurality of divided molds disposed along the circumference of thefoaming cavity.

Additionally, the slide mold 111 may move forward and backward via acylinder unit (not shown), and may move forward and backward along withthe reciprocating motion of a piston rod of the cylinder unit.

Furthermore, a slide mold 121 may be disposed separately within thesecond mold 120. The slide mold 121 may operate similarly to the slidemold 111. The slide mold 121 of the second mold 120 may move forward andbackward in an oblique direction. In this configuration, when the firstmold 110 and the second mold 120 are in closed state (e.g., combinedstate), the slide mold 111 of the first mold 110 and the slide mold 121of the second mold 120 may seal the skin forming cavity when movingforward.

In particular, the slide mold 111 of the first mold 110 may seal theskin forming cavity, and may form a skin forming cavity that correspondsto the skin shape, the edge portion of which may be inwardly bent.Additionally, the slide mold 121 of the second mold 120 may be aseparate slide mold that seals the skin forming cavity together with theslide mold 111 of the first mold 110.

The slide molds 111 and 121 may form a portion of the skin formingcavity when moving forward. When the slide mold 111 of the first mold110 and the slide mold 121 of the second mold 120 both move forward,upon injection molding of the skin as shown in FIG. 7A, the slide mold111 and the slide mold 121 may vertically engage with each other whilemaintaining a gap substantially equal to the thickness of the skin.

In particular, the front end portion of the slide mold 111 of the firstmold 110, which has a concave shape, may form a portion of the skin thatis inwardly bent, and thus the skin shape, the edge portion of which isinwardly bent, may be formed (see the skin injection molding of FIG. 7a). In other words, when the slide mold 111 of the first mold 110horizontally moves toward the center and the slide mold 121 of thesecond mold 120 obliquely moves (e.g., rises vertically), the first andsecond molds 111 and 121 may engage with each other, enabling the edgeportion of the skin 2 to have the shape described above.

Hereinafter, a process of manufacturing a crash pad using the moldingapparatus having the configuration described above will be described indetail with reference to FIGS. 7A and 7B.

First, a vacuum pressure may be applied to the vacuum aperture 114 ofthe first mold 110 that forms the skin by driving a vacuum pump, andthen a unique color of thread 115 may be inserted into and seated in thefixing groove 113 to allow the thread 115 to be adsorbed and fixed tothe fixing groove 113 via a vacuum suctioning force applied through thevacuum apertures 114 disposed at a predetermined interval (see the firstview of FIG. 7A) In particular, the thread 115 may have the same coloras the skin 2, or may have a different unique color from that of theskin 2.

Thereafter, the first mold 110 and the second mold 120, and the thirdmold 130 and the fourth mold 140 may be combined, and when the slidemolds 111 and 121 disposed within the first mold 110 and the second mold120 move forward, molten resin of the core material and molten resin ofthe skin material may be injected through the injection passageways 121and 141 of the second mold 120 and the fourth mold 140, respectively, tosimultaneously injection mold the core 1 and the skin 2 (see the secondview of FIG. 7A).

Furthermore, when the foaming is completed, the slide mold 121 of thesecond mold 120 may move backward, and then the first mold 110 and thethird mold 130 may be lifted to open each mold. The first mold 110 andthe fourth mold 140 used as the foaming mold may be combined by movingthe molds, and then the foaming layer 3 may be formed by injectingfoaming liquid through the foaming liquid injection passageway 141 ofthe fourth mold 140 (see the first view of FIG. 7B). In particular, whenthe slide mold 111 of the first mold 110 moves forward, the skin 2 andthe core 1 may be adhered closely to each other to seal the edge portionof the foaming cavity, and foaming liquid may be prevented from leakingby injecting foaming liquid into the sealed foaming cavity.

Thereafter, the first mold 110 and the third mold 130 may be lifted toopen each mold, and then a product (e.g., the crash pad) may be ejected(see the second view of FIG. 7B). Since the skin 2 may be maintained atan adhesion state with the surface of the core 1 while being fixed byfoaming liquid at the edge portion of the ejected product (e.g., noleakage of foaming liquid), a separate skin cutting process or skin endfinishing process (e.g., end enfolding process) may be omitted.

FIG. 8 is an exemplary view illustrating a process of forming a stitchon the surface of the skin using a thread. In FIGS. 8A and 8B, the firstview on the top illustrates the thread 115 adsorbed and fixed to theinner side of the fixing groove 113 via a suctioning force appliedthrough the vacuum aperture 114 before the skin forming process. Thesecond view illustrates the injection molding of the skin performed whenthe thread 115 blocks the vacuum aperture 114. The third viewillustrates a product ejected by releasing vacuum when the foaming layer3 is formed after the injection of the core and the skin 2.

The thread 115 may be adsorbed by the vacuum apertures 114 disposed at apredetermined interval, and then the skin 2 may be injection molded.Thus, the thread 115 may be fixed on the surface of the skin 2, and aportion of the thread 115 may be exposed to the surface of the skin 2 toform the stitch.

The crash pad manufactured according to this exemplary embodiment mayhave a stitch including an exposure part 115 a in which the thread 115may be exposed on the surface of the skin 2 and a hidden part 115 b inwhich the thread 115 may be inserted (e.g., buried) in the surface ofthe skin 2. In particular, the exposure part 115 a of the stitch may bea portion where the thread 115 is exposed on the surface of the skin 2,and the hidden part 115 of the stitch may be a portion where the thread115 is covered by the skin material (see FIG. 9).

Upon injection molding, at least a sectional portion of the thread 115may be inserted into the injection liquid, and then may be fixed in thesurface of the molded skin 2 while being inserted into the skin 2. Inparticular, when the injection liquid is injected while the thread 115is being fixed to the inner side of the fixing groove 113 of the firstmold 110, a first portion of the thread 115 adsorbed to the vacuumaperture 114, i.e., a first portion of the thread 115 that blocks thevacuum aperture 114 may be adhered closely to the surface of the mold110 via the vacuum suctioning force applied through the vacuum solution114. Accordingly, the first portion of the thread 115 may prevent apenetration of injection liquid between the thread 115 and the mold 110(see FIG. 8A). Thus, since the injection liquid may not penetratebetween the thread 115 and the mold 110 at the first portion of thethread 115 adsorbed to the vacuum aperture 114, the sectional upper partof the thread 115 may be exposed to the exterior from the surface of theskin 2. Accordingly, the first portion of the thread 115 may become theexposure part 115 a exposed to the exterior from the surface of the skin2 that is molded.

On the other hand, a second portion of the thread 115 not directlyadsorbed to the vacuum aperture 114 may be fully inserted in the skin 2due to the penetration of the injection liquid between thread 115 andthe mold 110, and thus the section upper part of the thread 115 may notbe exposed but hidden from the outside. In particular, a portion of theskin surface that is formed to cover the thread due to the penetrationof the injection liquid may become the hidden part 115 b, and the hiddenpart 115 b may be inserted to prevent being exposed when viewed from theexterior.

In brief, since the thread 115 may be adhered closely to the vacuumaperture 114 such that injection liquid does not penetrate uponinjection molding of the skin 2, a first portion of thread 115 exposedto the exterior of the skin surface may become the exposure part 115 a.In addition, since the thread 115 may be buried by the injection liquidpenetrating upon injection molding of the skin 2, a second portion ofthe skin material covering the thread 115 may become the hidden part 115b.

As shown in FIG. 8A, since the thread 115 blocks the vacuum aperture 114while being adhered closely to the inner surface of the fixing groove113 via a vacuum suctioning force, injection liquid may not penetratebetween the mold 110 and the thread 115 during the injection, and thusthe sectional upper part of the thread 115 may be exposed to theexterior of the surface of the skin 2, i.e., may become the exposurepart 115 a.

In addition, as shown in FIG. 8B, the injection liquid may penetrateinto a portion where the vacuum suctioning force does not directly act,particularly, a gap with a substantially low suction force, i.e., a gapbetween the inner surface of the fixing groove 113 of the mold 110 andthe thread 115. In this case, the injection liquid that penetrates maypush down the thread 115, and cover the upper part of the thread 115.Thus, the thread 115 may be inserted into the surface of the skin 2 thatis molded, and may not be exposed to the exterior at the hidden part 115b.

FIG. 9 illustrates a thread fixed to the surface of the skin. As shownin FIG. 9, the exposure part 115 in which the thread is exposed to theexterior by a predetermined length and the hidden part 115 b in whichthe thread is externally hidden at a predetermined interval may exist onthe surface of the skin 2.

It has been described in the above that a portion of the thread adheredclosely to the mold (e.g., inner surface of the fixing groove 113) 110such that the injection liquid does not penetrate by the vacuumsuctioning force applied through the vacuum aperture 114 may become theexposure part 115, and the a portion formed by the penetration of theinjection liquid between the mold 110 and the thread 115 due to a lowsuctioning force may become the hidden part 115 b. The length of theexposure part 115 a and the hidden part 115 b may be adjusted based onthe size and interval of the vacuum apertures 114 and the vacuumsuctioning force.

Particularly, although the size and interval of the vacuum apertures 114may be preset after the manufacture of the mold, a section where theinjection liquid may not penetrate may be formed at a portion of thethread that does not correspond to the vacuum aperture 114 of the mold110 by adjusting the sizes of the vacuum pressure and the vacuumsuctioning force, and furthermore, the length of the section where theinjection liquid penetrates may be adjusted.

Accordingly, the length and interval of the exposure part 115 a and thelength and interval of the hidden part 115 b may be adjusted. Inaddition, as the vacuum suctioning force increases, the length of theexposure part 115 a and the interval of the hidden part 115 b mayincrease. On the other hand, as the vacuum suctioning force decreases,the length of the hidden part 115 b and the interval of the exposurepart 115 a may increase. In particular, the vacuum suctioning force maybe applied to such an extent that the injection liquid may not penetrateinto the vacuum aperture 114 while the thread 115 is substantiallyblocking the vacuum aperture 114.

The apparatus and method for manufacturing a crash pad according to anexemplary embodiment of the present invention may improve theproductivity and decrease the costs for equipment and manufacturing byreducing the number of molds, the number of installation components andthe number of processes and omitting the handwork, and may increase thedegree of freedom of embossment design on the surface of a skin whileovercoming an excessive loss due to a leakage of foaming liquid.

Particularly, since the skin may be manufactured by injection molding, asmaller capacity of vacuum pump and tank may be used, and a heater maybe omitted. Additionally, various embossment patterns may be formed onthe surface of the skin. The realistic feeling of a stitch may beimproved by implementing a stitch part formed on the surface of the skinusing an actual thread.

The invention has been described in detail with reference to exemplaryembodiments thereof. However, it will be appreciated by those skilled inthe art that changes may be made in these embodiments without departingfrom the principles and spirit of the invention, the scope of which isdefined in the accompanying claims and their equivalents.

What is claimed is:
 1. A method for manufacturing a crash pad with afoaming layer formed by injecting foaming solution between a core and askin, the method comprising: adsorbing and fixing a thread to aninternal surface of a first mold to block a plurality of vacuumapertures disposed at a predetermined interval along a longitudinaldirection of the thread when a vacuum pressure is applied to each of thevacuum aperture, the thread forming a stitch part on a surface of theskin; forming the skin by injecting molten resin of a skin material whenthe first mold and a second mold are combined; forming the core byinjecting molten resin of a core material when a third mold and a fourthmold are combined; and forming a foaming layer by injecting foamingliquid into a foaming cavity between the core and the skin after themold are opened to combine the first mold fixed with the skin and thefourth mold attached with the core, wherein a first portion of thethread is adsorbed and fixed by a vacuum suctioning force of acorresponding vacuum aperture to form an exposure part of the stitch inwhich the thread is exposed on the surface of the skin and a secondportion of the thread is not adsorbed to the corresponding vacuumaperture to form a hidden part of the stitch in which the thread isburied in the surface of the skin.
 2. The method of claim 1, wherein alength and an interval of the exposure part and the hidden part areadjusted by the vacuum pressure.
 3. The method of claim 1, wherein thethread is seated and fixed in a fixing groove, wherein a suctioninginlet of the corresponding vacuum aperture is disposed at an inner sideof the fixing groove within the first mold.
 4. The method of claim 1,further comprising: combining the first mold and the second mold andmoving a slide mold disposed within the first mold to seal the skinforming cavity that corresponds to a shape of the skin, an edge portionof which is inwardly bent.
 5. The method of claim 4, further comprising:sealing a skin forming cavity by combining the first mold and the secondmold and moving forward a separate slide mold disposed within the secondmold.
 6. The method of claim 4, wherein the forming of the foaming layercomprises: sealing the foaming cavity by adhering an edge portion of theskin to an edge portion of the core using the slide mold.
 7. A crash padmanufactured by a method according to claim 1, the crash pad comprisinga stitch part comprising the exposure part and the hidden part.